Good erosion resistance (durability to resist erosion of molten filler) is required for aluminum alloy brazing sheets for use in automobile heat exchangers and the like. So far, in a brazing sheet having an Al—Si—Mn—Cu-based core material, for example, as described in JP-A-17116, deposition of dissolution elements such as Mn and Si has been suppressed by not performing a homogenizing process of the core material to coarsen the crystal grains in the post-braze core material heating and improve erosion resistance. In addition, Mg has been added to the core material to improve post-braze strength.
However, in brazing sheets produced by adding Mg to a core material, Mg—Si-based, Al—Mg—Cu-based or Al—Cu—Mg—Si-based intermetallic compounds may be produced depending on the heat treatment conditions during the manufacturing process. It has therefore been impossible to sufficiently improve erosion resistance by conventional methods only.